Abstract
A simple steady-state model for a 3-species mixture (ions, electrons, and neutrals) in a screw-pinch plasma configuration is developed. The model is applied to the central plasma column of the PROTO-SPHERA experiment. Degree of ionization, azimuthal current density, and azimuthal ion velocity are calculated. Full ionization is found at plasma temperatures above 1.5 eV, with neutrals confined in an outer shell where radial plasma flow develops and drives both azimuthal current and azimuthal flow.
Highlights
Confined plasmas are commonly formed inside a toroidal vacuum vessel surrounded by a toroidal magnet
Full ionization is found at plasma temperatures above 1.5 eV, with neutrals confined in an outer shell where radial plasma flow develops and drives both azimuthal current and azimuthal flow
The main result is that owing to the high PROTO-SPHERA densities, the plasma is fully ionized already at Te = 2 eV, well below the Ar first ionization energy
Summary
Confined plasmas are commonly formed inside a toroidal vacuum vessel surrounded by a toroidal magnet. The toroidal magnetic field is generated by current flowing in an axial plasma pinch (called the centerpost plasma discharge). The voltage difference between electrodes is regulated to drive the preset plasma current, which heats the plasma and generates the toroidal (azimuthal) magnetic field. The main properties of the centerpost plasma are the capability of conducting the desired current within the voltage limits of the power supply and the uniform spreading of current on the anode surface Such avoidance of anode arc-anchoring is likely due to spontaneous plasma rotation. The 1-D analysis for ions and electrons is similar to the one developed for magnetized gas discharge plasmas [6,7], but uniform neutral gas density was assumed in those works, while neutral dynamics is kept into account in this work.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call